git.maemo.org Git - busybox4maemo/blob - coreutils/dd.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Mini dd implementation for busybox
   4  *
   5  *
   6  * Copyright (C) 2000,2001  Matt Kraai
   7  *
   8  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
   9  */
  10
  11 #include <signal.h>  /* For FEATURE_DD_SIGNAL_HANDLING */
  12 #include "libbb.h"
  13
  14 /* This is a NOEXEC applet. Be very careful! */
  15
  16
  17 enum {
  18         ifd = STDIN_FILENO,
  19         ofd = STDOUT_FILENO,
  20 };
  21
  22 static const struct suffix_mult dd_suffixes[] = {
  23         { "c", 1 },
  24         { "w", 2 },
  25         { "b", 512 },
  26         { "kD", 1000 },
  27         { "k", 1024 },
  28         { "K", 1024 },  /* compat with coreutils dd */
  29         { "MD", 1000000 },
  30         { "M", 1048576 },
  31         { "GD", 1000000000 },
  32         { "G", 1073741824 },
  33         { }
  34 };
  35
  36 struct globals {
  37         off_t out_full, out_part, in_full, in_part;
  38 };
  39 #define G (*(struct globals*)&bb_common_bufsiz1)
  40 /* We have to zero it out because of NOEXEC */
  41 #define INIT_G() memset(&G, 0, sizeof(G))
  42
  43
  44 static void dd_output_status(int ATTRIBUTE_UNUSED cur_signal)
  45 {
  46         /* Deliberately using %u, not %d */
  47         fprintf(stderr, "%"OFF_FMT"u+%"OFF_FMT"u records in\n"
  48                         "%"OFF_FMT"u+%"OFF_FMT"u records out\n",
  49                         G.in_full, G.in_part,
  50                         G.out_full, G.out_part);
  51 }
  52
  53 static ssize_t full_write_or_warn(const void *buf, size_t len,
  54         const char *const filename)
  55 {
  56         ssize_t n = full_write(ofd, buf, len);
  57         if (n < 0)
  58                 bb_perror_msg("writing '%s'", filename);
  59         return n;
  60 }
  61
  62 static bool write_and_stats(const void *buf, size_t len, size_t obs,
  63         const char *filename)
  64 {
  65         ssize_t n = full_write_or_warn(buf, len, filename);
  66         if (n < 0)
  67                 return 1;
  68         if (n == obs)
  69                 G.out_full++;
  70         else if (n) /* > 0 */
  71                 G.out_part++;
  72         return 0;
  73 }
  74
  75 #if ENABLE_LFS
  76 #define XATOU_SFX xatoull_sfx
  77 #else
  78 #define XATOU_SFX xatoul_sfx
  79 #endif
  80
  81 int dd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  82 int dd_main(int argc, char **argv)
  83 {
  84         enum {
  85                 FLAG_SYNC    = 1 << 0,
  86                 FLAG_NOERROR = 1 << 1,
  87                 FLAG_NOTRUNC = 1 << 2,
  88                 FLAG_TWOBUFS = 1 << 3,
  89                 FLAG_COUNT   = 1 << 4,
  90         };
  91         static const char keywords[] ALIGN1 =
  92                 "bs=\0""count=\0""seek=\0""skip=\0""if=\0""of=\0"
  93 #if ENABLE_FEATURE_DD_IBS_OBS
  94                 "ibs=\0""obs=\0""conv=\0""notrunc\0""sync\0""noerror\0"
  95 #endif
  96                 ;
  97         enum {
  98                 OP_bs = 1,
  99                 OP_count,
 100                 OP_seek,
 101                 OP_skip,
 102                 OP_if,
 103                 OP_of,
 104 #if ENABLE_FEATURE_DD_IBS_OBS
 105                 OP_ibs,
 106                 OP_obs,
 107                 OP_conv,
 108                 OP_conv_notrunc,
 109                 OP_conv_sync,
 110                 OP_conv_noerror,
 111 #endif
 112         };
 113         int exitcode = EXIT_FAILURE;
 114         size_t ibs = 512, obs = 512;
 115         ssize_t n, w;
 116         char *ibuf, *obuf;
 117         /* And these are all zeroed at once! */
 118         struct {
 119                 int flags;
 120                 size_t oc;
 121                 off_t count;
 122                 off_t seek, skip;
 123                 const char *infile, *outfile;
 124         } Z;
 125 #define flags   (Z.flags  )
 126 #define oc      (Z.oc     )
 127 #define count   (Z.count  )
 128 #define seek    (Z.seek   )
 129 #define skip    (Z.skip   )
 130 #define infile  (Z.infile )
 131 #define outfile (Z.outfile)
 132
 133         memset(&Z, 0, sizeof(Z));
 134         INIT_G();
 135         //fflush(NULL); - is this needed because of NOEXEC?
 136
 137 #if ENABLE_FEATURE_DD_SIGNAL_HANDLING
 138         signal_SA_RESTART_empty_mask(SIGUSR1, dd_output_status);
 139 #endif
 140
 141         for (n = 1; n < argc; n++) {
 142                 smalluint key_len;
 143                 smalluint what;
 144                 char *key;
 145                 char *arg = argv[n];
 146
 147 //XXX:FIXME: we reject plain "dd --" This would cost ~20 bytes, so..
 148 //if (*arg == '-' && *++arg == '-' && !*++arg) continue;
 149                 key = strstr(arg, "=");
 150                 if (key == NULL)
 151                         bb_show_usage();
 152                 key_len = key - arg + 1;
 153                 key = xstrndup(arg, key_len);
 154                 what = index_in_strings(keywords, key) + 1;
 155                 if (ENABLE_FEATURE_CLEAN_UP)
 156                         free(key);
 157                 if (what == 0)
 158                         bb_show_usage();
 159                 arg += key_len;
 160 #if ENABLE_FEATURE_DD_IBS_OBS
 161                 if (what == OP_ibs) {
 162                         /* Must fit into positive ssize_t */
 163                         ibs = xatoul_range_sfx(arg, 1, ((size_t)-1L)/2, dd_suffixes);
 164                         continue;
 165                 }
 166                 if (what == OP_obs) {
 167                         obs = xatoul_range_sfx(arg, 1, ((size_t)-1L)/2, dd_suffixes);
 168                         continue;
 169                 }
 170                 if (what == OP_conv) {
 171                         while (1) {
 172                                 /* find ',', replace them with NUL so we can use arg for
 173                                  * index_in_strings() without copying.
 174                                  * We rely on arg being non-null, else strchr would fault.
 175                                  */
 176                                 key = strchr(arg, ',');
 177                                 if (key)
 178                                         *key = '\0';
 179                                 what = index_in_strings(keywords, arg) + 1;
 180                                 if (what < OP_conv_notrunc)
 181                                         bb_error_msg_and_die(bb_msg_invalid_arg, arg, "conv");
 182                                 if (what == OP_conv_notrunc)
 183                                         flags |= FLAG_NOTRUNC;
 184                                 if (what == OP_conv_sync)
 185                                         flags |= FLAG_SYNC;
 186                                 if (what == OP_conv_noerror)
 187                                         flags |= FLAG_NOERROR;
 188                                 if (!key) /* no ',' left, so this was the last specifier */
 189                                         break;
 190                                 arg = key + 1; /* skip this keyword and ',' */
 191                         }
 192                         continue;
 193                 }
 194 #endif
 195                 if (what == OP_bs) {
 196                         ibs = obs = xatoul_range_sfx(arg, 1, ((size_t)-1L)/2, dd_suffixes);
 197                         continue;
 198                 }
 199                 /* These can be large: */
 200                 if (what == OP_count) {
 201                         flags |= FLAG_COUNT;
 202                         count = XATOU_SFX(arg, dd_suffixes);
 203                         continue;
 204                 }
 205                 if (what == OP_seek) {
 206                         seek = XATOU_SFX(arg, dd_suffixes);
 207                         continue;
 208                 }
 209                 if (what == OP_skip) {
 210                         skip = XATOU_SFX(arg, dd_suffixes);
 211                         continue;
 212                 }
 213                 if (what == OP_if) {
 214                         infile = arg;
 215                         continue;
 216                 }
 217                 if (what == OP_of)
 218                         outfile = arg;
 219         }
 220 //XXX:FIXME for huge ibs or obs, malloc'ing them isn't the brightest idea ever
 221         ibuf = obuf = xmalloc(ibs);
 222         if (ibs != obs) {
 223                 flags |= FLAG_TWOBUFS;
 224                 obuf = xmalloc(obs);
 225         }
 226         if (infile != NULL)
 227                 xmove_fd(xopen(infile, O_RDONLY), ifd);
 228         else {
 229                 infile = bb_msg_standard_input;
 230         }
 231         if (outfile != NULL) {
 232                 int oflag = O_WRONLY | O_CREAT;
 233
 234                 if (!seek && !(flags & FLAG_NOTRUNC))
 235                         oflag |= O_TRUNC;
 236
 237                 xmove_fd(xopen(outfile, oflag), ofd);
 238
 239                 if (seek && !(flags & FLAG_NOTRUNC)) {
 240                         if (ftruncate(ofd, seek * obs) < 0) {
 241                                 struct stat st;
 242
 243                                 if (fstat(ofd, &st) < 0 || S_ISREG(st.st_mode) ||
 244                                                 S_ISDIR(st.st_mode))
 245                                         goto die_outfile;
 246                         }
 247                 }
 248         } else {
 249                 outfile = bb_msg_standard_output;
 250         }
 251         if (skip) {
 252                 if (lseek(ifd, skip * ibs, SEEK_CUR) < 0) {
 253                         while (skip-- > 0) {
 254                                 n = safe_read(ifd, ibuf, ibs);
 255                                 if (n < 0)
 256                                         goto die_infile;
 257                                 if (n == 0)
 258                                         break;
 259                         }
 260                 }
 261         }
 262         if (seek) {
 263                 if (lseek(ofd, seek * obs, SEEK_CUR) < 0)
 264                         goto die_outfile;
 265         }
 266
 267         while (!(flags & FLAG_COUNT) || (G.in_full + G.in_part != count)) {
 268                 if (flags & FLAG_NOERROR) /* Pre-zero the buffer if conv=noerror */
 269                         memset(ibuf, 0, ibs);
 270                 n = safe_read(ifd, ibuf, ibs);
 271                 if (n == 0)
 272                         break;
 273                 if (n < 0) {
 274                         if (!(flags & FLAG_NOERROR))
 275                                 goto die_infile;
 276                         n = ibs;
 277                         bb_simple_perror_msg(infile);
 278                 }
 279                 if ((size_t)n == ibs)
 280                         G.in_full++;
 281                 else {
 282                         G.in_part++;
 283                         if (flags & FLAG_SYNC) {
 284                                 memset(ibuf + n, '\0', ibs - n);
 285                                 n = ibs;
 286                         }
 287                 }
 288                 if (flags & FLAG_TWOBUFS) {
 289                         char *tmp = ibuf;
 290                         while (n) {
 291                                 size_t d = obs - oc;
 292
 293                                 if (d > n)
 294                                         d = n;
 295                                 memcpy(obuf + oc, tmp, d);
 296                                 n -= d;
 297                                 tmp += d;
 298                                 oc += d;
 299                                 if (oc == obs) {
 300                                         if (write_and_stats(obuf, obs, obs, outfile))
 301                                                 goto out_status;
 302                                         oc = 0;
 303                                 }
 304                         }
 305                 } else if (write_and_stats(ibuf, n, obs, outfile))
 306                         goto out_status;
 307         }
 308
 309         if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
 310                 w = full_write_or_warn(obuf, oc, outfile);
 311                 if (w < 0) goto out_status;
 312                 if (w > 0)
 313                         G.out_part++;
 314         }
 315         if (close(ifd) < 0) {
 316  die_infile:
 317                 bb_simple_perror_msg_and_die(infile);
 318         }
 319
 320         if (close(ofd) < 0) {
 321  die_outfile:
 322                 bb_simple_perror_msg_and_die(outfile);
 323         }
 324
 325         exitcode = EXIT_SUCCESS;
 326  out_status:
 327         dd_output_status(0);
 328
 329         return exitcode;
 330 }